From 50ae726bb349868d9d22b71fb7c24c2f9c2f32bd Mon Sep 17 00:00:00 2001
From: Xing Xue <xingxue@outlook.com>
Date: Thu, 18 Dec 2025 08:27:10 -0500
Subject: [PATCH] [libc++][AIX] Move to new locale APIs (#172068)

This patch moves to the new locale base APIs for AIX.

Co-authored-by: Nikolas Klauser <nikolasklauser@berlin.de>
---
 libcxx/include/CMakeLists.txt                 |   1 +
 libcxx/include/__locale_dir/locale_base_api.h |   4 +-
 libcxx/include/__locale_dir/support/aix.h     | 296 ++++++++++++++++++
 libcxx/include/module.modulemap.in            |   1 +
 4 files changed, 301 insertions(+), 1 deletion(-)
 create mode 100644 libcxx/include/__locale_dir/support/aix.h

diff --git a/libcxx/include/CMakeLists.txt b/libcxx/include/CMakeLists.txt
index 53ca1f7d3ded..e6d5d444cc1c 100644
--- a/libcxx/include/CMakeLists.txt
+++ b/libcxx/include/CMakeLists.txt
@@ -527,6 +527,7 @@ set(files
   __locale_dir/num.h
   __locale_dir/pad_and_output.h
   __locale_dir/scan_keyword.h
+  __locale_dir/support/aix.h
   __locale_dir/support/apple.h
   __locale_dir/support/bsd_like.h
   __locale_dir/support/freebsd.h
diff --git a/libcxx/include/__locale_dir/locale_base_api.h b/libcxx/include/__locale_dir/locale_base_api.h
index a5849dfa3a07..0474c1db359d 100644
--- a/libcxx/include/__locale_dir/locale_base_api.h
+++ b/libcxx/include/__locale_dir/locale_base_api.h
@@ -120,13 +120,15 @@
 #    include <__locale_dir/support/linux.h>
 #  elif _LIBCPP_LIBC_NEWLIB
 #    include <__locale_dir/support/newlib.h>
+#  elif defined(_AIX)
+#    include <__locale_dir/support/aix.h>
 #  else
 
 // TODO: This is a temporary definition to bridge between the old way we defined the locale base API
 //       (by providing global non-reserved names) and the new API. As we move individual platforms
 //       towards the new way of defining the locale base API, this should disappear since each platform
 //       will define those directly.
-#    if defined(_AIX) || defined(__MVS__)
+#    if defined(__MVS__)
 #      include <__locale_dir/locale_base_api/ibm.h>
 #    elif defined(__OpenBSD__)
 #      include <__locale_dir/locale_base_api/openbsd.h>
diff --git a/libcxx/include/__locale_dir/support/aix.h b/libcxx/include/__locale_dir/support/aix.h
new file mode 100644
index 000000000000..a216e2839379
--- /dev/null
+++ b/libcxx/include/__locale_dir/support/aix.h
@@ -0,0 +1,296 @@
+//===-----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___LOCALE_DIR_SUPPORT_AIX_H
+#define _LIBCPP___LOCALE_DIR_SUPPORT_AIX_H
+
+#include <__config>
+#include <__cstddef/size_t.h>
+#include <__std_mbstate_t.h>
+#include <__utility/forward.h>
+#include <clocale> // std::lconv
+#include <cstdio>
+#include <cstdlib>
+#include <ctype.h>
+#include <string.h>
+#include <time.h>
+#if _LIBCPP_HAS_WIDE_CHARACTERS
+#  include <cwchar>
+#  include <wctype.h>
+#endif
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+namespace __locale {
+
+struct __locale_guard {
+  _LIBCPP_HIDE_FROM_ABI __locale_guard(locale_t& __loc) : __old_loc_(::uselocale(__loc)) {}
+
+  _LIBCPP_HIDE_FROM_ABI ~__locale_guard() {
+    if (__old_loc_)
+      ::uselocale(__old_loc_);
+  }
+
+  locale_t __old_loc_;
+
+  __locale_guard(__locale_guard const&)            = delete;
+  __locale_guard& operator=(__locale_guard const&) = delete;
+};
+
+//
+// Locale management
+//
+#define _LIBCPP_COLLATE_MASK LC_COLLATE_MASK
+#define _LIBCPP_CTYPE_MASK LC_CTYPE_MASK
+#define _LIBCPP_MONETARY_MASK LC_MONETARY_MASK
+#define _LIBCPP_NUMERIC_MASK LC_NUMERIC_MASK
+#define _LIBCPP_TIME_MASK LC_TIME_MASK
+#define _LIBCPP_MESSAGES_MASK LC_MESSAGES_MASK
+#define _LIBCPP_ALL_MASK LC_ALL_MASK
+#define _LIBCPP_LC_ALL LC_ALL
+
+// Get MB_CUE_MAX before __locale_t is defined because it uses a defferent definition in <sys/localedef.h>.
+inline _LIBCPP_HIDE_FROM_ABI decltype(MB_CUR_MAX) __mb_cur_max() { return MB_CUR_MAX; }
+
+using __locale_t _LIBCPP_NODEBUG = ::locale_t;
+
+#if defined(_LIBCPP_BUILDING_LIBRARY)
+using __lconv_t _LIBCPP_NODEBUG = std::lconv;
+
+inline _LIBCPP_HIDE_FROM_ABI __locale_t __newlocale(int __category_mask, const char* __locale, __locale_t __base) {
+  return ::newlocale(__category_mask, __locale, __base);
+}
+
+inline _LIBCPP_HIDE_FROM_ABI void __freelocale(__locale_t __loc) { ::freelocale(__loc); }
+
+inline _LIBCPP_HIDE_FROM_ABI char* __setlocale(int __category, char const* __locale) {
+  return ::setlocale(__category, __locale);
+}
+
+inline _LIBCPP_HIDE_FROM_ABI __lconv_t* __localeconv(__locale_t& __loc) {
+  __locale_guard __current(__loc);
+  return std::localeconv();
+}
+#endif // _LIBCPP_BUILDING_LIBRARY
+
+// The following structure is a quick-and-dirty workaround for routines that AIX
+// does not provide in the "_l" (locale-aware) variants.
+struct __setAndRestore {
+  explicit __setAndRestore(locale_t locale) {
+    if (locale == (locale_t)0) {
+      __cloc   = newlocale(LC_ALL_MASK, "C", /* base */ (locale_t)0);
+      __stored = uselocale(__cloc);
+    } else {
+      __stored = uselocale(locale);
+    }
+  }
+
+  ~__setAndRestore() {
+    uselocale(__stored);
+    if (__cloc)
+      freelocale(__cloc);
+  }
+
+private:
+  locale_t __stored = (locale_t)0;
+  locale_t __cloc   = (locale_t)0;
+};
+
+//
+// Strtonum functions
+//
+inline _LIBCPP_HIDE_FROM_ABI float __strtof(const char* __nptr, char** __endptr, __locale_t __loc) {
+  __setAndRestore __newloc(__loc);
+  return ::strtof(__nptr, __endptr);
+}
+
+inline _LIBCPP_HIDE_FROM_ABI double __strtod(const char* __nptr, char** __endptr, __locale_t __loc) {
+  __setAndRestore __newloc(__loc);
+  return ::strtod(__nptr, __endptr);
+}
+
+inline _LIBCPP_HIDE_FROM_ABI long double __strtold(const char* __nptr, char** __endptr, __locale_t __loc) {
+  __setAndRestore __newloc(__loc);
+  return ::strtold(__nptr, __endptr);
+}
+
+//
+// Character manipulation functions
+//
+#if defined(_LIBCPP_BUILDING_LIBRARY)
+inline _LIBCPP_HIDE_FROM_ABI int __toupper(int __c, __locale_t __loc) { return toupper_l(__c, __loc); }
+
+inline _LIBCPP_HIDE_FROM_ABI int __tolower(int __c, __locale_t __loc) { return tolower_l(__c, __loc); }
+
+inline _LIBCPP_HIDE_FROM_ABI int __strcoll(const char* __s1, const char* __s2, __locale_t __loc) {
+  return strcoll_l(__s1, __s2, __loc);
+}
+
+inline _LIBCPP_HIDE_FROM_ABI size_t __strxfrm(char* __dest, const char* __src, size_t __n, __locale_t __loc) {
+  return strxfrm_l(__dest, __src, __n, __loc);
+}
+
+#  if _LIBCPP_HAS_WIDE_CHARACTERS
+inline _LIBCPP_HIDE_FROM_ABI int __iswctype(wint_t __c, wctype_t __type, __locale_t __loc) {
+  return iswctype_l(__c, __type, __loc);
+}
+
+inline _LIBCPP_HIDE_FROM_ABI int __iswspace(wint_t __c, __locale_t __loc) { return iswspace_l(__c, __loc); }
+
+inline _LIBCPP_HIDE_FROM_ABI int __iswprint(wint_t __c, __locale_t __loc) { return iswprint_l(__c, __loc); }
+
+inline _LIBCPP_HIDE_FROM_ABI int __iswcntrl(wint_t __c, __locale_t __loc) { return iswcntrl_l(__c, __loc); }
+
+inline _LIBCPP_HIDE_FROM_ABI int __iswupper(wint_t __c, __locale_t __loc) { return iswupper_l(__c, __loc); }
+
+inline _LIBCPP_HIDE_FROM_ABI int __iswlower(wint_t __c, __locale_t __loc) { return iswlower_l(__c, __loc); }
+
+inline _LIBCPP_HIDE_FROM_ABI int __iswalpha(wint_t __c, __locale_t __loc) { return iswalpha_l(__c, __loc); }
+
+inline _LIBCPP_HIDE_FROM_ABI int __iswblank(wint_t __c, __locale_t __loc) { return iswblank_l(__c, __loc); }
+
+inline _LIBCPP_HIDE_FROM_ABI int __iswdigit(wint_t __c, __locale_t __loc) { return iswdigit_l(__c, __loc); }
+
+inline _LIBCPP_HIDE_FROM_ABI int __iswpunct(wint_t __c, __locale_t __loc) { return iswpunct_l(__c, __loc); }
+
+inline _LIBCPP_HIDE_FROM_ABI int __iswxdigit(wint_t __c, __locale_t __loc) { return iswxdigit_l(__c, __loc); }
+
+inline _LIBCPP_HIDE_FROM_ABI wint_t __towupper(wint_t __c, __locale_t __loc) { return towupper_l(__c, __loc); }
+
+inline _LIBCPP_HIDE_FROM_ABI wint_t __towlower(wint_t __c, __locale_t __loc) { return towlower_l(__c, __loc); }
+
+inline _LIBCPP_HIDE_FROM_ABI int __wcscoll(const wchar_t* __ws1, const wchar_t* __ws2, __locale_t __loc) {
+  return wcscoll_l(__ws1, __ws2, __loc);
+}
+
+inline _LIBCPP_HIDE_FROM_ABI size_t __wcsxfrm(wchar_t* __dest, const wchar_t* __src, size_t __n, __locale_t __loc) {
+  return wcsxfrm_l(__dest, __src, __n, __loc);
+}
+#  endif // _LIBCPP_HAS_WIDE_CHARACTERS
+
+inline _LIBCPP_HIDE_FROM_ABI
+size_t __strftime(char* __s, size_t __max, const char* __format, const struct tm* __tm, __locale_t __loc) {
+  return strftime_l(__s, __max, __format, __tm, __loc);
+}
+
+//
+// Other functions
+//
+inline _LIBCPP_HIDE_FROM_ABI decltype(__mb_cur_max()) __mb_len_max(__locale_t __loc) {
+  __locale_guard __current(__loc);
+  return __mb_cur_max();
+}
+
+#  if _LIBCPP_HAS_WIDE_CHARACTERS
+inline _LIBCPP_HIDE_FROM_ABI wint_t __btowc(int __c, __locale_t __loc) {
+  __locale_guard __current(__loc);
+  return std::btowc(__c);
+}
+
+inline _LIBCPP_HIDE_FROM_ABI int __wctob(wint_t __c, __locale_t __loc) {
+  __locale_guard __current(__loc);
+  return std::wctob(__c);
+}
+
+inline _LIBCPP_HIDE_FROM_ABI size_t
+__wcsnrtombs(char* __dest, const wchar_t** __src, size_t __nwc, size_t __len, mbstate_t* __ps, __locale_t __loc) {
+  __locale_guard __current(__loc);
+  return ::wcsnrtombs(__dest, __src, __nwc, __len, __ps); // non-standard
+}
+
+inline _LIBCPP_HIDE_FROM_ABI size_t __wcrtomb(char* __s, wchar_t __wc, mbstate_t* __ps, __locale_t __loc) {
+  __locale_guard __current(__loc);
+  return std::wcrtomb(__s, __wc, __ps);
+}
+
+inline _LIBCPP_HIDE_FROM_ABI size_t
+__mbsnrtowcs(wchar_t* __dest, const char** __src, size_t __nms, size_t __len, mbstate_t* __ps, __locale_t __loc) {
+  __locale_guard __current(__loc);
+  return ::mbsnrtowcs(__dest, __src, __nms, __len, __ps); // non-standard
+}
+
+inline _LIBCPP_HIDE_FROM_ABI size_t
+__mbrtowc(wchar_t* __pwc, const char* __s, size_t __n, mbstate_t* __ps, __locale_t __loc) {
+  __locale_guard __current(__loc);
+  return std::mbrtowc(__pwc, __s, __n, __ps);
+}
+
+inline _LIBCPP_HIDE_FROM_ABI int __mbtowc(wchar_t* __pwc, const char* __pmb, size_t __max, __locale_t __loc) {
+  __locale_guard __current(__loc);
+  return std::mbtowc(__pwc, __pmb, __max);
+}
+
+inline _LIBCPP_HIDE_FROM_ABI size_t __mbrlen(const char* __s, size_t __n, mbstate_t* __ps, __locale_t __loc) {
+  __locale_guard __current(__loc);
+  return std::mbrlen(__s, __n, __ps);
+}
+
+inline _LIBCPP_HIDE_FROM_ABI size_t
+__mbsrtowcs(wchar_t* __dest, const char** __src, size_t __len, mbstate_t* __ps, __locale_t __loc) {
+  __locale_guard __current(__loc);
+  return std::mbsrtowcs(__dest, __src, __len, __ps);
+}
+#  endif // _LIBCPP_HAS_WIDE_CHARACTERS
+#endif   // _LIBCPP_BUILDING_LIBRARY
+
+_LIBCPP_DIAGNOSTIC_PUSH
+_LIBCPP_CLANG_DIAGNOSTIC_IGNORED("-Wgcc-compat")
+_LIBCPP_GCC_DIAGNOSTIC_IGNORED("-Wformat-nonliteral") // GCC doesn't support [[gnu::format]] on variadic templates
+#ifdef _LIBCPP_COMPILER_CLANG_BASED
+#  define _LIBCPP_VARIADIC_ATTRIBUTE_FORMAT(...) _LIBCPP_ATTRIBUTE_FORMAT(__VA_ARGS__)
+#else
+#  define _LIBCPP_VARIADIC_ATTRIBUTE_FORMAT(...) /* nothing */
+#endif
+
+template <class... _Args>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_VARIADIC_ATTRIBUTE_FORMAT(__printf__, 4, 5) int __snprintf(
+    char* __s, size_t __n, __locale_t __loc, const char* __format, _Args&&... __args) {
+  __locale_guard __current(__loc);
+  return std::snprintf(__s, __n, __format, std::forward<_Args>(__args)...);
+}
+
+template <class... _Args>
+inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_VARIADIC_ATTRIBUTE_FORMAT(__printf__, 3, 4) int __asprintf(
+    char** __s, __locale_t __loc, const char* __format, _Args&&... __args) {
+  __locale_guard __current(__loc);
+
+  // Probe exact size.
+  int n = std::snprintf(nullptr, 0, __format, std::forward<_Args>(__args)...);
+  if (n < 0) {
+    *__s = nullptr;
+    return -1;
+  }
+
+  // Allocate and render once
+  size_t buf_size = static_cast<size_t>(n) + 1;
+  char* buf       = static_cast<char*>(std::malloc(buf_size));
+  if (!buf) {
+    *__s = nullptr;
+    return -1;
+  }
+
+  int written_size = std::snprintf(buf, buf_size, __format, std::forward<_Args>(__args)...);
+  if (written_size < 0) {
+    std::free(buf);
+    *__s = nullptr;
+    return -1;
+  }
+
+  *__s = buf;
+  return written_size;
+}
+_LIBCPP_DIAGNOSTIC_POP
+#undef _LIBCPP_VARIADIC_ATTRIBUTE_FORMAT
+
+} // namespace __locale
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___LOCALE_DIR_SUPPORT_AIX_H
diff --git a/libcxx/include/module.modulemap.in b/libcxx/include/module.modulemap.in
index 04be734e3738..feb6249e1e6d 100644
--- a/libcxx/include/module.modulemap.in
+++ b/libcxx/include/module.modulemap.in
@@ -1578,6 +1578,7 @@ module std [system] {
     }
 
     module support_impl {
+      textual header "__locale_dir/support/aix.h"
       textual header "__locale_dir/support/apple.h"
       textual header "__locale_dir/support/bsd_like.h"
       textual header "__locale_dir/support/freebsd.h"